 The lower gastrointestinal tract lacks the alcohol dehydrogenase enzyme present in the stomach and liver that breaks down ethanol into acetylaldehyde, which is actually more toxic than ethanol (drinking alcohol) and is responsible for most chronic effects of ethanol.When rectally absorbed, ethanol will still eventually arrive at the liver, but the high alcohol content could overwhelm the organ.Additionally, consuming the alcohol rectally neutralizes the body's ability to reject the toxin by vomiting.